Added split tap to TouchExplorationController

ui/chromeos/touch_exploration_controller.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_CHROMEOS_TOUCH_EXPLORATION_CONTROLLER_H_
 #define UI_CHROMEOS_TOUCH_EXPLORATION_CONTROLLER_H_
 
 #include "base/timer/timer.h"
 #include "base/values.h"
 #include "ui/chromeos/ui_chromeos_export.h"
@@ skipping 18 matching lines @@
 // ** Short version **
 //
 // At a high-level, single-finger events are used for accessibility -
 // exploring the screen gets turned into mouse moves (which can then be
 // spoken by an accessibility service running), a double-tap simulates a
 // click, and gestures can be used to send high-level accessibility commands.
 // When two or more fingers are pressed initially, from then on the events
 // are passed through, but with the initial finger removed - so if you swipe
 // down with two fingers, the running app will see a one-finger swipe.
 //
 // ** Long version **

[dmazzoni, 2014/06/16 18:21:19]

You should update the description in the header file to include an explanation
of how split-tap works.

[evy, 2014/06/16 20:34:20]

Done.

 //
 // Here are the details of the implementation:
 //
 // When the first touch is pressed, a 300 ms grace period timer starts.
 //
 // If the user keeps their finger down for more than 300 ms and doesn't
 // perform a supported accessibility gesture in that time (e.g. swipe right),
 // they enter touch exploration mode, and all movements are translated into
 // synthesized mouse move events.
 //
@@ skipping 48 matching lines @@
   ui::EventRewriteStatus InSingleTapPressed(
       const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event);
   ui::EventRewriteStatus InSingleTapReleased(
       const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event);
   ui::EventRewriteStatus InDoubleTapPressed(
       const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event);
   ui::EventRewriteStatus InTouchExploration(
       const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event);
   ui::EventRewriteStatus InPassthroughMinusOne(
       const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event);
-
+  ui::EventRewriteStatus InTouchExplSecondPress(
+      const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event);
   // This timer is started every time we get the first press event, and
   // it fires after the double-click timeout elapses (300 ms by default).
   // If the user taps and releases within 300 ms and doesn't press again,
   // we treat that as a single mouse move (touch exploration) event.
   void OnTapTimerFired();
 
   // Dispatch a new event outside of the event rewriting flow.
   void DispatchEvent(ui::Event* event);
 
   scoped_ptr<ui::Event> CreateMouseMoveEvent(const gfx::PointF& location,
@@ skipping 33 matching lines @@
 
     // The user placed two or more fingers down within the grace period.
     // We're now in passthrough mode until all fingers are lifted. Initially
     // the first finger is ignored and other fingers are passed through
     // as-is. If a finger other than the initial one is the first to be
     // released, we rewrite the first finger with the touch id of the finger
     // that was released, from now on. The motivation for this is that if
     // the user starts a scroll with 2 fingers, they can release either one
     // and continue the scrolling.
     PASSTHROUGH_MINUS_ONE,
+
+    // The user was in touch exploration, but has placed down another finger.
+    // If the user releases the second finger, a touch press and release
+    // will go through at the last touch explore location. If the user
+    // releases the touch explore finger, the other finger will continue with
+    // touch explore. Any fingers pressed past the first two are ignored.
+    TE_SECOND_PRESS,

[dmazzoni, 2014/06/16 18:21:19]

I'd prefer TOUCH_EXPL_SECOND_PRESS or something like that here - TE is a bit too
short. I'd be fine with agreeing on something even more concise too, like
TOUCHEX, and especially if we used it consistently throughout the file.

[evy, 2014/06/16 20:34:20]

Done. I think I'll stick with TOUCH_EXPL_SECOND_PRESS like the function right
now, and we find that there are a lot more states/functions that need to be
added that refer to touch exploration, I might change it to something shorter at
that point.

   };
 
   void VLOGState(int line_number);
 
   void VLOGEvent(const ui::Event& event, int line_number);
 
   // Gets enum name from integer value
   const char* EnumStateToString(State state);
 
   const char* EnumEventTypeToString(ui::EventType type);
@@ skipping 13 matching lines @@
   int initial_touch_id_passthrough_mapping_;
 
   // The current state.
   State state_;
 
   // A copy of the event from the initial touch press.
   scoped_ptr<ui::TouchEvent> initial_press_;
 
   // The last location where we synthesized a mouse move event.
   // When the user double-taps, we send the passed-through tap here.
-  gfx::PointF last_touch_exploration_location_;
+  scoped_ptr<ui::TouchEvent> last_touch_exploration_;
 
   // A timer to fire the mouse move event after the double-tap delay.
   base::OneShotTimer<TouchExplorationController> tap_timer_;
 
   // For testing only, an event handler to use for generated events
   // outside of the normal event rewriting flow.
   ui::EventHandler* event_handler_for_testing_;
 
   // A default gesture detector config, so we can share the same
   // timeout and pixel slop constants.
   ui::GestureDetector::Config gesture_detector_config_;
 
   // The previous state entered
   State prev_state_;
 
   // The previous EventType
   ui::EventType prev_event_;
 
   DISALLOW_COPY_AND_ASSIGN(TouchExplorationController);
 };
 
 }  // namespace ui
 
 #endif  // UI_CHROMEOS_TOUCH_EXPLORATION_CONTROLLER_H_